In order to perform communication, a user equipment (UE) present in a cell of cellular communication accesses a base station (BS), receives control information for transmitting and receiving data to and from a base station (BS), and then transmits and receives data to and from the BS. That is, since the UE transmits and receives data through the BS, the UE transmits data of the UE to the BS in order to transmit data to another cellular UE, and the BS that receives the data transmits the received data to another UE. As such, in order to transmit data from one UE to another UE, the data can be transmitted only through the BS, and thus the BS performs scheduling on a resource and channel for data transmission and reception and transmits channel and resource scheduling information to each UE. For communication between UEs through the BS, each UE requires channel and resource allocation for data transmission and reception from the BS, but device-to-device (D2D) communication is configured in such a way that a UE directly transmits and receives a signal to and from a target UE subjected to data transmission without a BS or a relay.
D2D communication is a distribute communication scheme for directly transmitting traffic between adjacent nodes without infrastructure such as a BS. In a D2D communication environment, each node such as a portable UE, etc. searches for another physically adjacent UE, configures communication sessions, and then transmits the traffic. As such, D2D communication can distribute traffic concentrated on an eNB to overcome traffic overload, and thus has drawn attention as main technology of post-4G next-generation mobile communication technology. For this reason, standardization institutes such as 3GPP, IEEE, etc. have established D2D communication standards based on LTE-A or Wi-Fi and Qualcomm, etc. have developed independent D2D communication technology.